1. Technical Field
This application relates to auditory spatial perception and, more particularly, to estimating an auditory source width of a sound in a loudspeakers-room system.
2. Related Art
The perceived acoustic quality of a sound source may depend on the acoustic characteristics of the structures in the vicinity of the sound source. As a sound propagates away from its source, a portion of the sound reaches the listener as direct sound that follows a straight path from the source to the listener's ear. A large portion of the sound, however, radiates in all directions from the source and encounters boundaries (e.g., walls). The combined direct sound and reflections that arrive at the listener's ear cause auditory spatial perception. The reflected sound may be delayed and frequency colored. The delay, frequency coloration, and reverberation of sound events in the spatial (3D) dimensions of a room may be captured and interpreted to give humans an auditory perception of the sound system and the space in which a sound travels.
The sound reflections may be classified as early lateral reflections and late reflections. The relationship of early lateral reflections with direct sound may be used to determine the direction and location of the sound source. Due to the reverberation characteristics of a listening room, the auditory source is perceived as exhibiting a finite lateral extent. Additionally, the temporal and spatial separation of sound energy of the late reflections causes the perception of being enveloped by the sound. This phenomenon is known as the listener envelopment.
The acoustic characteristics of various rooms often differ. A concert hall may have different acoustic characteristics than a vehicle compartment. The spatial auditory characteristics of a room may be classified through monaural parameters. These monaural parameters may be the Clarity C80 and Definition D50, the Early Decay Time Gap (EDTG), or Center Time TS. However, these parameters may not correlate with perceptible characteristics. Others may use binaural parameters to quantify the spatial auditory characteristics of a room. These binaural parameters may be the Interaural Cross-Correlation (IACC) or Lateral Energy Fraction (LEF). However, these parameters may significantly depend on the measurement position. Furthermore, a ranking of listener rooms (e.g., concert halls) based on such established parameters may not sufficiently match the actual auditory perception and preferences of human listeners.